You can't think of it in those terms. The film didn't really have a film speed of 98 because who develops the film within a minute of exposure? As hold times should be longer than two hours for film speed testing, the speed is actually more like 78. Hold time is a frequently overlooked variable in film speed testing.
Film would be even faster if it were possible to process within fractions of a second. Reciprocity failure is actually a form of latent image regression.
Traditional fine grain films have more uniform grains. As a group, they tend to either be able to be developed or not. That's why they tended toward higher contrast compared to the same levels of development as faster films, and why litho films are very fine and uniformly grained.